Optical apparatus



1,647,016 Oct. 25 1927- P. REAVES oPTIdA AAAAAAAA US Oct. 25 1927.

W. P. REAVES OPTI CAL APPARATUS Filed Sept. 1922 '7 Sheets-Sheet 2 1,64016 Oct. 25, 1927. w. R REM/Es I H OPTICAL APPARATUS Filed Sept. 0. 19227 Sheets-Sheet 3 7/4 I 71' g 5. Y

@51 WM, 2 MM mm,

2 192 Oct 5 7 w. P. REAvEs OPTICAL APPARATUS Filed Sept. 2 1922 '7SheetsSheet 4 l/ m 7. mfifi g A, Z W W m MW 5 m W. P. REAVES OPTICALAPPARATUS Filed Sept. 20. 1922 7 Sheets-Sheet 6 Oct.

m mm,

Oct, 25,1927. w. P. REM/Es 1,647,016

OPTICAL APPARATUS Filed Sept. 20. 1922 7 Sheets-Sheet 7 Patented Oct.25, 1927.

UNITED STATES WILLIAM P. REAVES, OF GREENSBORO, NORTH CAROLINA.

OPTICAL APPARATUS.

Application filed September 20, 1922.

The present invention relates to an apparatus for testing visual acuity.

The object of the invention is to provide a convenient apparatus of thecabinet type having a number or elements for subjecting a patient to aseries of tests of vision, the

elements being of the general type well known to retractionists, such asa chart having letters or objects inscribed thereon of diti'erent sizeas measured in visual acuity units, a meridian dial and a rotatableastigmatic chart, these elements being associated, however, in a novelcombination and being adapted to be controlled by the examiningretractionist from a testing point whereby they may be operatedsimultaneously or in conjunction with each other. Associated with theseelements is means for controlling the degree of their illumination andalso means for testing the ability of the patients eyes to recognizevarious colors. These last mentioned means are also manipulated by therefractionist from a distant point, preterably from a position at theside of the patient-so that he is enabled to present these tests inrapid succession and without movement which might tend to distract thepatient s attention. The retl'ractionist is thus stationed at the mostadvantageous point for conducting the test, having at hand means forcontrolling the machine which is located some distance away and alsohaving within reach the various test lenses commonly used in thecorrection of defects of vision, as well as being conveniently placed toenter the data obtained by the test upon suitable record sheets.

As previously pointed out, the invention contemplates the use of achart, a meridian dial and a rotatable astigmatic chart, these elementsbeing coordinate and operatively connected for simultaneous operation.The main chart has thereon a series of letters or objects. theastigmatic chart a series of disks. each having lines inscribed thereonin one or two directions, or other test ob jects, and the meridian dialconsists in a series of lines radiating from a common center, which isthe center of the astigmatic chart, these lines being arranged atintervals of 7 around a complete semicircle.

'ihe chart is mounted. upon rollers and has a plurality of letters ortest objects thereon,

Serial No. 7589,4623.

the astigmatic chart has a. plurality of lines, squares, or objects, andthe radial lines of the meridian dial are variable in width, the threetest objects being so coordinate that they present to the eyesimultaneously lines of equal value when measured in visual acuityunits. The refractionist is enabled by manipulation of his controls tosimultaneously move the test chart, theastigmatic chart, and to vary thewidth of the lines of the meridian dial, but at least one line ofletters or objects on the test chart will be of the same value whenmeasured in visual acuity units as the lines of the astigmatic chart andthe meridian dial. The patient is therefore presented simultaneouslywith three test devices of the same value, having vertical, horizontalor oblique dimensionsso that the error of his refraction in any meridianmay be obtained by the use of test lenses.

In general, his attention is first directed to the chart. then to thedial, and then to the astigmatic chart, but this order may be varied asdesired. By the aid of a :test chart a test is given which shows theacute ness otvision to the unaided eye. The retract-ionist by the use ofthe chart and with test lenses of the usual kind is enabled to reachcertain conclusions as to his patients acuity of vision. If the eye hasequal resolving power in all meridians the error is measured-by.spherical lenses. When the eye has unequal resolving power thedifference of theerrors in the two principal meridians is measured bythe cylindrical lenses. This is a subjective test of the eyes by the useof lenses and test card. The accuracy otthe test is increased bycombining with it the objective test of the dial and disc. A moredelicate test is by the dial, the black lines being a groove or V shapewhich prevents reflexes or halations and make them appear intenselyblack, and by increasing the Fig. 4c is a section on line 4l of Fig. 2;Fig. 5 is a section on line 55 of 2; "Fig.6 is arsectionon line 66 ofF1g.-2;

Fig. 7 is a side View of the machine showing the control means;

Fig. 8 is a detail view; 7 Fig. 9 is ase'ction on line 99 of Fig. 3;

Figs. 10, 1 1, 12 and 13 are details; Fig. '14 is a diagrammaticrepresentatlon of the lighting mechanism;

Fig. 15 is a view of a portionof the apparatus as seen from the rear ofthe casing; and r Fig. 16 Fig. 3;:

The casing in which the several test ob- ;jects and mechanism foroperating the same is a section on line 1616of are'housed may be formedin any c0nvenient manner. In the present instance the casing has a boxlike lowerportion and a semicylindrical upper portion, as clearlyshownin Figs. 1 and 2. The front face of the casingis indicated at 10,the rear face at 11, and the side plates at 13 and 14 respectively.The'upper edges of the front and rear plates are semicircular andparallel and the semicylindrical coveror hood member 15 hasits edgessecured to the iedgesof these platesrespectively. The front plate 10 isprovidedwith three major open1ngs, a lowerrectangular opening 16, acentral circularopeninglfland an upper opening 18 in the formof asemicircular and relatively wideslot, these three openings constitutingview openings through which thetest objects may beseen from'the frontofthe apparatus. Through the upper openings 18 the patientmay observe aseries of blades or lines equal inwidth and disposed along linesradiating from acommoncenter and spaced 5 apart throughout a halfcircle. Through the'central opening the patient may observe a chartelement having a line, object, or series of lines thereon which may bearranged at right angles, the several. lines being ofequal width, and.throughthe lower opening 16 n ay be observed one or more linesofletters or objectsof a char;

In Fig. 6 thecabinet is shown as it would appear from the front if the,face plate were .re'moved.. 'It will beus'een that the letterchart-20lis of a flexible nature, its ends being.

secured torolls121 and 22, the axles23 and '2 E'Q WhiQh ar Pa ll ers-jae in the pedestals 25 and 26. Lines of letters are inscribed orengrossed on the chart, which letters vary in size from very largeletters to very small ones, as is usual in eye testing charts of thischaracter.

The astigmatic chart comprises a disk 27 rotatable about a tired axisand having thereon a series of smaller disks or chart elements 28 whichare rotatable relatively to thelarge disk. These chart elements havelines inscribed thereon as shown, the lines being of different widths onthe different disks, but it will be understood that lines or testobjects of any desired character, may be inscribed on the chartelements. Only one disk is visible to the observer at a time and thearrangement -is such that as this disk comes into register with theviewopening 17 the lines of the disk will be horizontally and verticallydisposed and the movements of the astigmatic chart and the mainor letterchart 20 are so synchronizedthat the linesof the visible chart element28 have the same value as measured in visual acuity units as at leastone visible line of letters of the main chart 20. I

The meridian dial comprises a series of blades L radiating from a commoncenter, which in this case is coaxial with the center of the visiblechart element 28, and the arrangement is such that the'seeming width ofthemeridiandines maybe variedso that these lines have at any onetime thesame value, as measured in visual acuity units, as

r the lines of the visible chart element 28, or

one line of letters of the letter chart 20. By

means of a single cord, which may be ma nipulated by the refractionistfrom his posit1on ad acent thepatients side, three test devices may besimultaneously manipulated to present test objects of different values,as desired, and the mechanism for performing this'function will now bedescribed in detail.

' Referring particularly to Fig. 2 it will be seen that the disk 27 uponwhich the chart elements 28 are rotatably mounted is secured to arotatable shaft 30 mounted in the, vertically disposed plate or bracket31. ilm circular frames 32to which the disks or chart elements 28 aresecured are mounted in ball bearings 39.which permit their free rotationrelatively to the main supporting disk 27;. Each frame 32 is providedwith a toothed wheel 34 at its rear and the tOUtl'leCl wheels of all ofthe chart elements 28 mesh with a central gear wheel 35'which is looselymounted on the shaft 30 but'i's normally held from rotation; The meansfor normally preventing rotationof gear 35 coniprises a cord 36, one endof which is secured within the groove of a pulley; wheel '37 end ofwhich is connected spring 38 to the side wall of the frame Rotation of.CllSli. 27 therefore causes rotat on of all of the rigidlyattached tothe 35, and the other e chart elements 28, but the gears 34 and 35 areso designed that as each chart element 28 comes into register with theopening 17 the lines inscribed thereon will be horizontal or vertical orwill occupy a desired definite position.

Rotation of disk 27 is effected by means of an operating lever lO-oneend of which is secured to the shaft 41 which shaft is operativelyconnected to the shaft 30, the large gear 42 rigidly secured on shaft 41meshing with pinion 43 secured on shaft 30. A slight rotation of shaft41 will effect a considerable movement of disk 27, as can be seen fromthe arrangement of gears disclosed. To the free end of lever 40 isattached a weight 44 with a pin and slot connection, which weight isslidable vertically on guides 45. A cord 46 is attached to the end ofthe lever and passes vertically upward through the top of the housingand thence over pulleys 47 to the handle-weight 48, which exactlybalances the weight 44. The operator may, by moving the weight 48vertically move the weight 44 a corresponding distance to bring thedesired chart element 28 into view, and upon removing his hand thischart element will remain in the position to which it has been adjustedsince weights 44 and 48 exactly balance each other.

In testing eyes for astigmatism the refractionist may desire to rotatethe chart element visible to the patient so that lines of any degree ofobliquity may be presented. Means is therefore provided whereby eachchart element may be rotated at the will of the operator after it comesinto register-with the view opening 17 It will be seen that to the rearof each frame 32 is secured a. pin 82. This pin is adapted to be engagedby a catch 46' secured upon an annular frame 47 mounted in ball hearingsin a suitable aperture in the plate or pedestal 3 Rotation of frame 47results, therefore, in rotation of frame 32' and of thechart element 28.The frame 47 has a chain which operatively connects the same to the gear48 rigidly mounted on shaft 50, rotatably supported on pedestals 31 and51. Also rigidly secured on this shaft is a pinion 52 meshing with agear 53 rigidly secured to a second shaft 54 rotatably mounted on thepedestals 31 and 51. To the opposite end of the shaft 54 is secured anoperating lever 55, clearly shown in Fig. 5, the free'end of which hassecured thereto a weight 56. The end of a cord 57 extending through thecasing and over pulleysto the operating handle 58 is fastened to the endof lever The operating lever may be raised by pulling clownward on thehandle 58, which balances weight 56, and lowered by raising weight 58.The frame 47" is normally positioned as shown in Fig. 5and it willbewunderstood that in this position the catch 46' lies below the path ofmovement of the pins 32' around the shaft 30 so that no interferenceexists between the pins 32 and this catch, but the catch is in positionto engage the pin 32 of any chart element in register with the aperturel7 and to effect rotation of this element when frame 47 is rotated.

Rigidly mounted on shafts 23 and 24 which support the main chart, arepinions 60 and 61, and extending around these pinions is a chain 62which also extends rear wardly and around a sprocket wheel 63 rigidlymounted on a shaft 64. The shaft 64 also has thereon a bevel wheel 65which in turn meshes with a second bevel wheel secured on shaft 67. Thepinion G8 is also secured on shaft 67 and meshes with the main gear 42so that as the gear 42 is ro tated to effect rotation of disk 27simultaneous movement is imparted to the chart 20, and the gearing is soarranged and designed that for any movement or rotation of theastigmatic chart, such movement is imparted to the main chart that atleast one row of letters of the main or letter chart have a value equalto the lines of the chart element 28 which is visible through theaperture 17, as previously pointed out.

The meridian dial is described and claimed in my copending applicationSerial No, 579,235, filed August2, 1922, but its peculiar combinationwith the other elements of the eye testing apparatus will be hereinbrougl'it out. In Figs. 11 and 12 details of the radiating blades areclearly shown. The blades extend radially between two concentricsemicircular frame members 70 and 71 and are spaced 5 apart. While fromthe front of the machine the blade appears to be a single member andperfectly flat, it will be seen from the detailed drawings that eachblade in reality comprises two portions 72, 73 arranged to swingrelatively to each other from an open position, shown in fulllincs inFig. 12, to closed position, shown in dotted lines in this figure. AsSeen from the front the blades appear as single lines and may be made toappear either very narrow or quite broad, depending upon the adjustment.Bushings 74 and 7 5 are rotatably mounted in the frame members 70 and 71respectively. The blade portions 73 have their ends rigidly secured tothese rotatable bushings and blade portions 72 have secured to theirends spindles 76 and 77 which. extend through axial apertures inbushings 74 and 75. 'The blade portions are therefore rotatablerelatively to each other and also to the supporting frame members.

Secured to the bushing 7 5 is a segment 78 of gear and adjustablysecured by means of-a screw 7 9 to the spindle 77 is a second gearsegment 80. These gear segments are cut away as shown in Fig. 10 so thatthey 7 into this cam slot.

may have some relative movement of rotation. The two segments meslrwithoppositely facing racks formed on a semicircular rack member 81, thearrangement being such that movement of this rack member longi tudinallyresults in opening and closing of the blades. The blades are sopositioned that an observer in front of the machine sees directly into aV-shaped space between them, in otherwordshe is looking into: anaperture from which no reflection of light is possible.

The ends of the semicircular rack81 are secured toa rocking beam 82clearly shown inuFigj16, which beam is hung from the flange 83' strap84. so that it may be rotated about the center from which the blades ofthe meridian dial radiate. Secured to the beam 82 is a plate 85 having acam slot 86 therein. A pin 87 projects fromthe gear'i2 and extendsRotation of gear 42 7 therefore effectsmovement of the beam 82 andhenceopening and closing of the blades of the meridian dial. The cam is,so deg signed that for all adjustments of the lever the blades have thesame value to: the observer, measured in visual acuity units, as atleast one line of letters on the main chart, and the lines or objects onthe visible chart element 28. I Y r v The main chart 20 is illuminatedbymeans of two bulbs provided with a light shield 101. The chartelements 28 are translucent and are illuminated from behind by one ofthe three bulbs 102, any one of which may be placed axially of the viewaperture 17. It'will be seen that these three bulbs 102 are mountedupona circular plate 103 rotatably supported in acircular aperture inthe back plate 11 of the casing and removab'ly secured therein by clamps10 1. The axis of the plate 103 is eccentric to the axis of theviewaperture 17 "and by rotating the .plate 103 any one" of .thethreelamps may beplaced axially of thevie-w'aperture. .Each lamp has twocontacts connected thereto and these contacts are adapted to besuccessively brought into electrical contact with apair of stationarythe lamps into and. out of electrical circuit 1 is automaticallyperformed.

A light background for the meridian dial is indicated at 110. V Thisdial *is semicircular and is illuminated by one of lamps 102 so. thatthe blades of the meridian dialappear as black lines silhouetted againsta luminous background. For controlling the amount of of the pedestal 31by the annular The plate 103 may be turned bylight thrown on the;background-. by; the

along barsand the gap between the ad j acent edges of these shields maybe varied desired.

Associated with'the mechanism for rotating the astigmatic chart elements28 is the color testing means; in Fig. 1 it will be seen. that twosmall'apert res 11 6.are

provided in the face plate 10 immediately above'theiaperture.17. Behindthese openings are positioned small electric lamps 117 whicharesecuredto the frame member '70.

' Inter-posed however-between the lamps 117 and the View apertures 116is an annular flange 118 on the rotating annularframe 1-7. Secured inthis' fiange are a number of color test" lenses '119;so that when theselamps are lighted and the frame 47 is ro-.

tat-cdqby means of the lever 55,-different colors may be observed'fromthe front. It

is essential to resent 1. 'luralit of colored lights simultaneously tothe 'obse'rvers-eyes 120 extend drearwardlyfrom' the apertures in theface plate,-terminating' just in front of the flange 118, which tubesprevent leakage oflight from the lamps 117 to the other view apertures,and which also serve to shut out rays of light from the bulb 102 whenthe color"is not being used,-so that the patient will see nocolorsthrough the apertures 116. It vill be understood t-hat the lamps117 are shielded'to 'preventthepas sage of light raysr-earwardly.'irpointer 118 is fastened tothe fiange 118 in a radial linewith thecatch 46 andis adaptedfio co-'-- operate with the blades '11 of'themeridian dial for the purpose of pointing QUt-EJIYPHI ticularone to thepatient. By reason of'th'e fact that'it is in linewith "theic'a-tch' 16it will alsoserve to'indji'cat'e:theamount of rotation, in degrees, ofanyone of the astigmatic chart elements28 by pointing to a "blade. L\VlllCllllfLS 1ts inclination mjarked'as shown.

-A-single lamp is illustrated at'121 which may be observed, when."lighted, through a small :view aperture 122. r This lamp is preferablyred. and may be used to assist in mak ing the. well known muscle testfor-the eyes.

\ cuits is shown.

curedon the shaft 11.

When the lamp 121 is lighted it will be understood that the other lampsare not lighted.

In Fig. let a diagram of the lighting cir' The machine is adapted to belighted from the ordii'iary house electric lighting circuit, the mainsof which are indicated at 123 and a main control switch at 12.41. Thepositions and circuits of the several lamps above described areindicated and it will beseen that a barrel switch S is provided forcontrolling the circuits through the severalgroups of lamps. The switchS comprises essentially a cylinder of fiber or insulating material 125which, as shown in Fig. 2, is loosely mounted on the shaft 50. To thecylinder 125 is rigidly secured a pinion 126 which is connected by meansof a chain 126: to a large gear 126 rigidly se- As a result, rotation ofthe barrel switchis effected by movement on lever a0 and hencesimultaneously with. movement of the several charts.

The contact plates on. the surface cylinder 1 125- are indicated at 127,128, 129. A pair of spring lingers Ct cooperate with the plate 127,. asecond pair Z) cooperate with plate 128,- and? a third pair 0 cooperatewith plate 129. When the contact fingers a are in electricalv contactwith the plate 1.27, the main chart lights 100 and one of the centrallights 102 are illuminated. The color lights 117 and the muscle testlight 121 are not. The plate 127 is of considerable length and thiscontact is maintained for all adjustments of the test objects up tovsubstantially a maximum. At a certain point in the movement of the lever10, that is, as the lever is approaching its limitof travel in onedirection, the contact plate 127 disengages spring fingers a and thecircuit through the lamp 102 and the lamps 100 is broken. Immediatelythereafter contact is made by the spring fingers 7) with the plate 128and the color test lamps are lighted. Movement of the lever 40 may bediscontinued here and the patients eyes subjected to color tests. Afterthe completion of such color tests the lever 40 may be further moved aslight dis tance whereupon the lamps 117 are extinguished and the lamp121'lighted for the muscle test. When all tests are. completed the mainswitch 124 may be opened.

To one skilled in the art the many advantages of the apparatus abovedescribed willbe apparent and. it will also be obvious that theprinciples of the invention may have numerous different embodiments ofwhich that disclosed is an example.

Having thus described my invention, what I claim as new and desire tosecure by Let ters Patent is:

1. In an eye testing apparatus of the class described, in combination, asupport, a plu rality of chart elements each having one or more symbolsthereon by means of which the eyes of an observer may be subjected to anobjective test, a member movably mounted on the support and: upon whichthe chart elements are mounted forrotation about their individual axes,the movable member being designed: and constructed to bring the chartelements successively to the same position for successive. observation,and means for rotating the chartv element under observation about itsaxis, for the purpose set forth.

2., In an eye testing. apparatus of the class described, in combination,a support, a plu rality of. disk-like chart elements each ha ing oneor-more symbols thereon by means of which the eyes of an observer may besubjected to an objective test, a member pivotally mounted upon thesupport and upon whichthe chart elements are'mounted for rotation abouttheir individual axes, the to tatable member being designed and constructed to bring, the chart elements successivel'y to thesame position.for successive observationand: means for rotating the chart elementunder observation about its axis, for the purpose set forth.

3. The combination set forth in claim 2 in which the means for rotatingthe. chart element under observation effects the simultaneous rotationof all the chart elements as said member rotates on its axis.

4:- In an eye testing apparatus, in combination, a movable supportingmember, a plurality of individual chart elements mounted forrotation onsaid member, and means positioned adjacent said movable support forengaging, and rotating one of said chart ele ments brought into positionto be engaged thereby.

5, In an eye testing apparatus, in combination, a meridian dial havingaplurality of members whose elfective thickness asseen fromthe front canbe varied, a movable chart having a plurality of chart elements: withtest lines thereon of different values, and means forsinniltaneouslyoperating said dial and chart.

6. In an eye testing apparatus, in combination; a meridian. dial havinga pluralitv of radially disposed: blades, a field or background spacedto the rear of said dial, and means for illuminating said field,comprising; a lamp, positioned on the axis of said dial.

7. In an eye. testing apparatus, in combination, a movable memberhavinga plurality oft chart elements thereon, a movable letter chart, andconnections between said member and chart whereby they may be operatedin syn'chronism for the purpose ofbringing into the observers visionsymbols of the same value as measured in visual acuity units.

8. In an eye testing apparatus, in combination, a meridian dial havingblades of variable Width, a movable member having a plurality of chartelements thereon," and' means for moving said member and varying thewidth of said blades in synchronism for the purpose of bringing into theobservers vision symbols of the same value as measured in visual acuityunits,

9; In aneye testing apparatus, in combination, a meridian dial havingblades of va-- riable width, a movable member havlng a plurality ofchart elements thereon, a movable main or letter chart, and means forope ously operating the dialinember, and chart so that objects ofthesame value as measured in visual acuity units are presented to the(ab-- server. i l v 11. In an eye testing apparatus, a plurality ofmovable members each having test ole-- jects' inscribed thereon ofdifferent values, and means for moving said members to present differenttest objects to the eye of an ob server, said means coordinating saidmovable members so that at least two spaced testobjects, one being oneach member, have the same: value as measured in visual acuity units tocheck one against the other.

12. In. an eye testing apparatus, in combination, a stationaryplatehaving two-apertures, a lamp behind each aperture and a ro tatablemember intermediate the lamps and apertures and having a series ofcolored lenses therein whereby an observer in front of the platewillfisee. colored lightsthrough said apertures. v, i 1 v 18. In an.eye-testing apparatus, in combination, a casing, a plurality of eyetesting devices within the casing, mechanical means also within thecasing-thru whichsaid eye testing-devices may besimultaneously'operated, and second means for operating said firstmentioned means from a distant point.

14; In an eye testing apparatus, in combination, a casing, astigmatic,color and muscle testing devices positioned withinthe casing, mechanicalmeans'within the casing thru which said devicesmay be successivelyactuated, and second means for operating said first mentioned means froma distan point. i p

15. In an eye testing apparatus, in combination, a supporting. memberrotatable about afixed axis, a plurality of individual chart elementsrotatably supported upon said supporting members, a spring retractedmember engaging each of said elements for maintaining the samelinrotation about its individual aXis as the supporting member rotates, andmanually controlled means forrotating the chart elementsabout their axesagainst the actionofsaid spring. 7

16. In an eye testing apparatus, in combination, a member having a viewaperture therein, a movable supporting member, a chart carried thereby,a series of lamps of di'lterent intensities, and means for bringing anyone of said lamps in register with said view aperture to illuminate saidchart.

17. In an eye testing apparatus, in combination, a member having a Viewaperture therein, a movable supporting member, a

translucent chart carriedthereby, a series of electrlc lamps ordifferent intensltles in the rear of said chart, means for bringing aselected one of said lamps in line with said aperture and chart andmeans toclose thecircuit of the selected lamp;

18 111 an eye testing apparatus, in combmation, a cabinet having a frontand back,

a view aperture in said front, a rotatable member, a series of chartscarried thereby,

means to rotate said member to bring any individual chartin registerwith said apers ture, a CllSC rotatably mounted behind said member, aplurality of electric lamps of different intensities on said disc andnormally open circuited, means to rotate sald disc to bring a selectedlamp in line with the aper ture and selected chart, and to close itscircuit.

19. In an eye testing apparatus, in combination, a casing or. support, amovable let ter chart, a rotatable member having a plu rality oflinescharts thereon, a meridian dial having blades of variable width andsingle means for simultaneously operating said chart and rotatablemember and varying the width of said blades.

-20. In an eye testing apparatus,in combination, a movable letterchart,a series of.

selectable astigmati'c charts, an adjustable meridian dial, colortesting discs and a muscle test device, a lamp to illuminate said letterchart, a single lamp for said astigmatic charts and said dial, lamps forsaid color test discs and a lamp for the muscle 22. In an eyetestingapparatus, in com bination a meridian dial. consisting in avplurality of radial blades, a field or background spaced to the rear ofsaid dial, means for lighting said background comprising a lamppositioned on the axis of the dial, and means comprising semicircularshields coaxial with said lamp for con trolling the intensity ofillumination of said field.

23. In an eye testing apparatus, in combination, a meridian dialconsisting in a plurality of radial blades, a field or backgroundspaced'to the rear of said dial, means "for lighting said backgroundcomprising a lamp positioned on the axis of the dial, and a pair ofsimilar semicircular shields, coaxial with said lamp, and means foradjusting said shields in respect to each other to control the intensityof illumination of said field.

24. In an eye testing apparatus, in combination, a plurality ofadjustable test devices, means to control the adjustment thereof from adistance including a lever operatively connected to said devices, aWeight at one end 01 said lever, a cord connected to said Weight andextending to the remote operator, and a counter Weight on the remote endof said cord.

In testimony whereof I hereunto atfix my signature.

WILLIAM P. REAVES.

